Pete was almost correct but used the wrong syntax for ‘change’: ALTER TABLE mytable CHANGE `time` `time` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP Notice that you must repeat the column name. Also, make sure you are using backticks instead of single quotes to escape the column name time, which prevents it from being interpreted as the … Read more
Your ALTER TABLE statement implies mysql will have to re-write every single row of the table including the new column. Since you have more than 2 million rows, I would definitely expect it takes a significant amount of time, during which your server will likely be mostly IO-bound. You’d usually find it’s more performant to … Read more
You can easily do this using the following command. Any value of 0 will be turned into a 0 (BIT = false), anything else will be turned into 1 (BIT = true). ALTER TABLE dbo.YourTable ALTER COLUMN YourColumnName BIT The other option would be to create a new column of type BIT, fill it from … Read more
Mysql has a special syntax for dropping foreign key constraints: ALTER TABLE tbl_magazine_issue DROP FOREIGN KEY FK_tbl_magazine_issue_mst_users
Something like this: ALTER TABLE dbo.MyTable DROP COLUMN OldComputedColumn ALTER TABLE dbo.MyTable ADD OldComputedColumn AS OtherColumn + 10 Source
If empName is a VARCHAR(50) column: ALTER TABLE Employees MODIFY COLUMN empName VARCHAR(50) AFTER department; EDIT Per the comments, you can also do this: ALTER TABLE Employees CHANGE COLUMN empName empName VARCHAR(50) AFTER department; Note that the repetition of empName is deliberate. You have to tell MySQL that you want to keep the same column … Read more
your table: q1 | q2 | q3 | q4 | q5 you can also do ALTER TABLE yourtable ADD q6 VARCHAR( 255 ) after q5
You want the following: ALTER TABLE mytable MODIFY mycolumn VARCHAR(255); Columns are nullable by default. As long as the column is not declared UNIQUE or NOT NULL, there shouldn’t be any problems.
As of 2011 Yes you can, but you will be facing cross-browser compatibility issues: http://www.quirksmode.org/dom/changess.html As of 2016 Browser support has improved a lot (every browser is supported, including IE9+). The insertRule() method allows dynamic addition of rules to a stylesheet. With deleteRule(), you can remove existing rules from a stylesheet. Rules within a stylesheet … Read more